If you go on a stroll through the narrow streets of London's East End, whether in winter or in summer, on weekdays or on bank holidays, the chances are that you'll come across film-makers or photographers on the hunt for signs of the Jewish communities who once peopled this area. Soup kitchens, poor schools, vapour baths - these are the designated centres of what was, until recently, a submerged urbanism.

Such places are reminders of a time before the majority of Jews decamped north to Stamford Hill and Golders Green and were replaced by sojourners from Sylhet, many of whom are now drifting away from the area, too. Look closely and you'll spot the traces of their exodus, the ghost signatures of Bangladeshi aspiration and endeavour, the faded scripts of old leatherware shops, champion trimmers and halal grocers. The new incomers, other than motley crews of hipster entrepreneurs, are Lithuanians and Turks.

And so the dance goes on. A brash, unassimilable batch of foreigners becomes, however fractiously or slowly, accepted as part of the local and national fabric. They are soon replaced by another fresh cargo whom they attack for not being as deserving as themselves. Assimilated Jews in 19th-century London did this to the refugees fleeing pogroms in eastern Europe. Today, Bangladeshis trade and recycle vicious rumours about gun-wielding, teen-pimping Kurds and Slavs.

Immigration to Britain is a story that is always told in the present tense and using the most sensationalist language. But it is, as Robert Winder shows in his elegant and timely study, one of the most prosaic and historical narratives we have. Winder has culled a wide array of not easily accessible scholarship on the history of different minority groups in this country and from it constructed a portrait of the nation that should be required reading for those toxic spewers at Migration Watch and at the Express. Most valuable, not least in this age of ethnic particularism, is the way in which he strives to draw parallels between the receptions accorded to the various groups of refugees and fortune-seekers.

The book is full of useful facts and reminders. St George was a Turkish knight. Our national religion is Middle Eastern. Much of the flora and fauna that make up this green and pleasant land is not indigenous, but stems from distant and often colonial territories. Even the invocation of "true Anglo-Saxon stock" by cultural nationalists relies on exactly the kind of hyphenated identity politics of which they are normally scornful.

As Winder points out, by the time of the Norman conquest, "what we now think of as the archetypal English character was already a robust mixture of Mediterranean, Celtic, Saxon, Roman, Jute, Angle, Danish and Norwegian, all moulded and rain-streaked by the British climate and landscape". He argues that the introduction of feudalism by the Nor-mans laid the foundation of our class system, and that it was the busy enterprise of the Huguenots that made possible the golden period of Elizabethan expansion.

Bloody Foreigners is a directory of names now seen as part of the true-blue heritage of the nation but whose origins lie outside of these shores: architect and dramatist John Vanbrugh; inventor John Dollond; financier Nathan Rothschild; Marks & Spencer co-founder Michael Marks; pianist Alfred Brendel; Siegfried Bettman, who created the Triumph; and Shami Ahmed, founder of Madchester fashion label Joe Bloggs and now a major shareholder in Moss Bros. To that list we might add a reference to The Unknown Worker - be it the Irish road-builder, the Malayan Lascar or the Punjabi seamstress - whose labours, though scantly rewarded, did so much to make the nation prosperous.

Exiles and revolutionaries have long considered the UK a safe haven. The imperial centre is a citadel for dissenters. One of its principal symbols is Speaker's Corner in Hyde Park. Voltaire noted in 1733: "The Jew, the Mohametan and the Christian transact together as though they all profess'd the same religion and give the name of infidel to none but bankrupts." In Winder's book, a new kind of national history emerges: one whose soul resides in urban spaces rather than in enclosed pasture lands; one that takes as much pleasure in the clamour of organ-grinders and street-chanters as it does in the sonorous toll of church bells; one whose continuity derives from successive waves of discontinuity.

This history has often been a dark one. Riots, if not formal segregation, have been common. In 1282, Jewish religious observance, even at home, was banned; eight years later, there was a mass expulsion of Jews from the country. In 1601, Elizabeth I issued a proclamation banishing the "great number of negars and Blackamoores which are crept into this realm". She did so on the grounds that they did not share the values of true-born Brits and that they were a drain on the public purse. In 1709, thousands of "poor Palatines" fled poverty and war in the Rhineland by making their way to London, where they were sheltered in a huge refugee camp at Blackheath. Soon mobs started to attack the asylum-seekers, some of whom were relocated to Liverpool or Ireland. Others were shipped to New York.

By the middle of the 20th century, immigration was seen in ethnic terms. The tens of thousands of Irish men and women escaping famine were often portrayed as little more than simians - Thomas Carlyle thought each of them was "a ready-made nucleus of degradation and disorder" - but over time they, like Poles and Hungarians, came to be seen as largely benign. It was postwar migration from the colonies - the return of the imperial repressed - that stoked the most agonised debates about the extent to which the nation's identity was being irrevocably transformed.

These days, many settlers are white. They come from Turkey, Romania and Lithuania. In Lambeth, the most widely spoken language after English is Yoruban, but it seems likely that it will soon be overtaken by Portuguese as a result of the great numbers of Brazilians who have moved to London in recent years. It's hard to keep abreast of such demographic shifts, not least because journalists are more interested in the private lives of celebrities than in delving into the rich and teeming stories of the exiles, wanderers and desperadoes who prepare their food, clean their offices and cab them home in the middle of the night.

Not for nothing do hundreds of thousands of foreigners try to come here rather than Belgium or Finland each year. Immigration, Winder rightly concludes, is "a tribute to our opportunity-rich economy, our humane (if overstretched) social services, our already polyglot culture, our historic civil liberties, and our rickety but ancient reputation for fairness and justice". Yet as his book shows, our image of ourselves as a unique island race and as a breed apart depends upon us spinning myths about our hostility to outsiders. It's no accident that it was an East End Jew, the novelist and playwright Israel Zangwill, who coined the term "melting pot" to describe New York in the first decade of the 20th century. The term would just as aptly describe the past 2,000 years of British history.

Sukhdev Sandhu is the author of London Calling: how black and Asian writers imagined a city (HarperCollins)